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  • Electronic Resource  (6)
  • Cell & Developmental Biology  (2)
  • Inorganic Chemistry  (2)
  • critical point  (2)
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  • Electronic Resource  (6)
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  • 1
    Electronic Resource
    Electronic Resource
    Measurement of Microkelvin Temperature Differences in a Critical-Point Thermostat (1998)
    Springer
    International journal of thermophysics 19 (1998), S. 481-490 
    Details
    ISSN: 1572-9567
    Keywords: critical point ; temperature control ; temperature gradients ; thermostat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The density of a pure fluid near its critical point is extremely sensitive to temperature gradients. In the absence of gravity, this effect limits the fluid's homogeneity. For example, at 0.6 mK above the critical temperature, the microgravity experiment Critical Viscosity of Xenon (CVX) can allow temperature differences no larger than 0.2 μK, corresponding to a gradient of 10−5 K·m−1. The CVX thermostat, which consists of a thick-walled copper cell contained within three concentric aluminum shells, was designed to achieve such a small temperature gradient. However, asymmetries not included in the thermostat's model could degrade the thermostat's performance. Therefore we measured the temperature gradient directly with a miniature commercial thermoelectric cooler consisting of 66 semiconductor thermocouples. We checked the results with a half-bridge consisting of two matched thermistors. The measurement was made along a thin-walled stainless-steel cell whose conductance was much lower than that of the copper cell, thus “amplifying” the temperature differences by a factor of 60. When the thermostat was controlled at a constant temperature, the steel cell's static temperature difference was 5±1 μK. (The value inferred for the copper cell is 0.08 μK.) Ramping the thermostat's temperature at a rate of 1 × 10−5 K·s−1 increased the temperature difference to 0.36 mK. These results demonstrate the feasibility of achieving extremely low temperature gradients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022521712860
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  • 2
    Electronic Resource
    Electronic Resource
    Viscosity measurements near a critical point using a novel torsion oscillator (1986)
    Springer
    International journal of thermophysics 7 (1986), S. 675-686 
    Details
    ISSN: 1572-9567
    Keywords: critical point ; cyclohexane ; methanol ; torsion oscillator ; viscometer ; viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A torsion-oscillator viscometer has been constructed for the measurement of the viscosity of fluids near both liquid-vapor and liquid-liquid critical points. This viscometer has a resolution of ±0.2% and operates at a low frequency (0.6 Hz) and a very low shear rate (0.05 Hz). Thus, it can be used closer to critical points than other viscometers before encountering the non-Newtonian phenomena associated with critical slowing down. This viscometer was used to study the viscosity anomaly near the consolute point of mixtures of methanol and cyclohexane along paths of constant pressure and paths of constant volume at temperatures spanning the range 10−5 〈 (T-T c)/T c〈10−2. The data are consistent with a simple, power-law divergence of the viscosity with a multiplicative background characterized by an apparent exponent y≈0.041. Recent theoretical estimates for y are near 0.033. If the data are to be fit with the theoretical value of y, one must simultaneously restrict the range of the data and introduce additional unphysical parameters into the fitting function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00502399
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  • 3
    Electronic Resource
    Electronic Resource
    Selenige Säure als neues spezifisches Reagens zur Bestimmung und Trennung für Wismut und Titan (1930)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 189 (1930), S. 101-112 
    Details
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1. Es wird die Eignung der selenigen Säure für analytische Zwecke gezeigt und.
    Additional Material: 12 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19301890110
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  • 4
    Electronic Resource
    Electronic Resource
    Differential induction of stromelysin mRNA by bovine articular chondrocytes treated with interferon-γ and interleukin-1α (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 154 (1993), S. 113-121 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Articular chondrocytes from rheumatoid joints have been shown to express class II major histocompatibility (MHC) antigens that were correlated with the presence of interferon-gamma (IFN-γ) in the inflamed joint. Chondrocytes expressing MHC antigens function as antigens function as antigen presenting cells and thus stimulate lymphocyte proliferation. These responses suggest a powerful role for the IFN-γ stimulation of chondrocytes. The present studies were designed to examine the functional role of chondrocytes exposed to IFN-γ during cartilage degradation that occurs in synovial disease. Destruction of cartilage in arthritis is partially attributable to metalloproteinases released by the chondrocytes in response to interleukin-1 (IL-1). Bovine articular chondrocytes treated with interleukin-1 alpha (IL-1α) produced enhanced levels of stromelysin mRNA, however, Northern blots could not determine the percentage of cells responding. Exposure of bovine articular chondrocytes to IFN-γ induced the expression of bovine HLA-DR (boHLA-DR) antigen in 50% of the cells. Using a modified cell sorting technique, chondrocytes that expressed class II MHC antigens produced two fold greater stromelysin mRNA than chondrocytes that did not express this antigen. In contrast, collagen type II mRNA levels were similar in chondrocytes, regardless of the expression of class II MHC antigens. In situ hybridization studies showed that less than half of all cartilage chondrocytes were induced to synthesize stromelysin mRNA. These observations suggest that IFN-γ stimulates specific subpopulations of chondrocytes to be functionally active in inflammation-induced metalloprotease secretion. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041540114
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  • 5
    Electronic Resource
    Electronic Resource
    On [Na(POCl3)4]+ Complex Ion Formation: Conductivity, Raman, and NMR studies in the system phosphoryl chloride-sodium tetrachloro aluminate and related compounds (1989)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 573 (1989), S. 170-184 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Über die Bildung von [Na(POCl3)4]+-Komplexionen. Leitfähigkeits-, Raman- und NMR-Untersuchungen im System Phosphorylchlorid-Natriumtetrachloroaluminat bzw. analoger VerbindungenLeitfähigkeiten, Raman- sowie 27Al-, 23Na- und 31P-NMR-Spektren des Systems POCl3-NaAlCl4 wurden in Abhängigkeit vom Molenbruch x(NaAlCl4) im lösungsmittelreichen Gebiet gemessen. Zusätzlich erfolgte die Registrierung der Raman-Spektren der Lösungen von NaFeCl4, LiAlCl4, LiFeCl4 und KAlCl4 in POCl3. In den Li+- bzw. Na+-Ionen enthaltenden Proben konnte unter bestimmten Bedingungen ein von Temperatur und Salzkonzentration abhängiger Phasenübergang von der flüssigen in die feste Phase beobachtet werden. Deutliche Veränderungen in den Ramanspektren der Elektrolytlösungen im Vergleich zum reinen Lösungsmittel POCl3 belegen die Existenz von intermolekularen Wechselwirkungen, durch die das POCl3-Molekül beeinflußt wird. Die Annahme der Bildung von [M(POCl3)4]+-Solvaten (M = Li, Na) aufgrund der Ramanergebnisse wird durch die Resultate der NMR-Spektroskopie unterstützt.
    Notes: The system POCl3-NaAlCl4 was investigated by measuring the conductivity and the Raman and NMR spectra (27Al, 23Na and 31P) as a function of the mol fraction x of NaAlCl4 in POCl3. Additionally, Raman spectra of POCl3 solutions of NaFeCl4, LiAlCl4, LiFeCl4, and KAlCl4 were recorded. In solutions containing Li+ or Na+ ions a liquid to solid (or jelly) phase transition was observed under certain conditions, dependent on salt concentration and temperature. Observed changes in the Raman spectra of the electrolyte solutions in comparison to the pure solvent POCl3 demonstrate the existence of interactions. Clearly, the POCl3 eigenfrequencies and hence the molecules are pertubed. The formation of [M(POCl3)4]+ complexes (M = Li, Na) can be deduced from the Raman measurements. NMR investigations support this conclusion. For assigning of Raman spectra, (Li+, K+) cation and ([FeCl4]-, [SbCl6]-) anion substitutions were employed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19895730117
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  • 6
    Electronic Resource
    Electronic Resource
    Enzyme-gold affinity labelling of cellulose (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 371-379 
    Details
    ISSN: 0741-0581
    Keywords: Casuarina ; Cellulase ; Cell walls ; Codium ; Colloidal gold ; Dictyostelium ; Udotea ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The enzyme-linked colloidal gold affinity labelling technique was tested as a method to localize cellulose on thin sections of plant cell walls and slime mold spores. Commercially available cellulase from cultures of Trichoderma reesei, the main components being cellobiohydrolase I and II (CBH I, CBH II) and endoglucanase (EG), was linked to colloidal gold by using standard techniques and applied as a dilute, buffered suspension to thin sections. After brief exposure, e.g., 15-30 minutes, cellulose exposed on the surface of sections was labelled with the enzyme-gold complex. Poststaining did not appear to have a deleterious effect on the labelled sections. The specificity of labelling was demonstrated by its complete inhibition when carboxymethylcellulose was incorporated in the labelling mixture, by lack of labelling of 1,4-β-mannans or 1,3-β-xylans in noncellulosic walls of marine algae, by lack of labelling of 1,4-β-glucans in chitin, by much lower labelling density when done at 4°C, and by lack of labelling when sections were predigested with cellulase. Labelling with the crude commercial cellulase was compared to labelling with purified CBH I-, CBH II-, and EG-linked colloidal gold, and the labelling pattern was similar. This method was found useful on conventionally fixed material and required no special preparation other than the use of inert (Ni or Au) grids and 0.5% gelatin to reduce nonspecific binding of the gold complex. Labelling was similar in the several embedding resins tested: LR White, Lowicryl K4M, Epon 812, and Spurr's. The cellulase-gold probe remained active for at least 4 weeks at 4°C and much longer when frozen at -80°C in 20% glycerol. This technique should prove useful in studies of cellulose degradation and cellulose deposition and of the interaction of cellulose with other wall components.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060080406
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